232 PHILOSOPHICAL TRANSACTIONS. [aNNO 1685 . 



the so called cinnabar of antimony.* He examines its constituent principles ; 

 explains the phaenomena which occur in its preparation ; and describes its me- 

 dicinal virtues. 



Some remarkable Effects of a great Storm of Thunder and Lightning at Ports- 

 mouth, Oct. 23, l683. N° 177, p. 1212. 



On board his Majesty's ship the RoyalJames, a flash of lightning and thunder 

 together struck the mast, which was put into her for careening, being a made 

 mast, and bound with iron hoops from one end to the other, and shivered it 

 down to the deck, breaking one of the iron hoops in the body of the mast, so 

 that splinters are forced out of the middle of the mast a foot and half long ; 

 so that the mast is wholly unserviceable, and must be taken out. At the same 

 time a ball of fire ran about the deck. 



On board the Coronation a great ball of fire came into the gun-room ports, 

 throwing a boy out of one of them, by which he was drowned ; and several 

 workmen on board were struck down, and remained senseless for some time ; 

 the fire-ball ran up and struck on the starboard side of the wardrobe, and left a 

 place scorched round on the side, and between the two ring-bolts, as if it had 

 been a shot ; and beat the wainscot over to the other side, all scorched as if 

 with fire ; it also ran up against and struck the doors and hinges ; and divided 

 into several fire-balls on the deck among the men ; some part of it also broke in 

 at the windows of the round-house, shivering off a great deal of the wainscot, 

 broke the glasses of a prospective, and made a hole through a letter that lay in 

 the window eight double, the size of a musket bullet, and no more ; it also 

 shivered the timber that holds the ensign staff on the poop. Portsmouth, 

 Oct. 24, 1685. 



On the tendency of the Needle to a Piece of Iron, held perpendicular, in several 

 Climates. By a Master of a Ship crossing the Equinoctial Line, ^nno J 684 ; 

 and communicated by Mr. Arthur Bayley, F. R. S. N° 177, ?• 1213. 

 All the way from England to 10° north latitude, the north point of the 



* What was formerly called cinnabar of antimony is a compound of sulphur and quicksilver. The 

 process for obtaining it consisted in mixing together and subjecting to sublimation well pulverised anti- 

 mony (sulphuret of antimony) and corrosive sublimate (oxymuriate of quicksilver). On the appli- 

 cation of heat the muriatic acid seized the antimony (with which it has a greater affinity) and formed 

 with it what was called butter of antimony (oxymuriate of antimony) while the disengaged sulphur 

 (the other conrnonent part of the crude antimony) united with the quicksilver, forming with it th 

 compound termed cinnabar (sulphuret of quicksilver). But cinnabar so prepared is not different froD} 

 common cinnabar, and the title cinnabar of antimony has only served to produce confusion. 



